1. Field of the Invention
The present invention is the technical area of displaying objects and landscapes in a virtual world, and pertains more particularly to managing lighting applied to the objects and landscape elements.
2. Description of Related Art
Virtual worlds, and processes and techniques for displaying objects and landscapes in such systems are well-known in the art. One example is the technical area of video games, which present dynamic renditions of characters (persons) often termed “avatars” in the art. Such dynamic video displays may be “first-person”, in which the sequential development is from the perspective of an avatar, or third-person, in which various moving objects and avatars may be displayed from a narrative perspective. In any case game videos typically present avatars and other objects that dynamically move in the progressing display, and physics calculations may be heavily incorporated to control how avatars and other objects react with one another, to lend as much of a sense of reality to the action displayed as possible and practical. A further important point is the nature of video games, that is, that they are interactive with at least one player, and may be interactive with a plurality of players. A player in such a game is enabled to manipulate an avatar through input mechanisms, and may be enabled for other parameters and effects as well, such as changing interactivity between avatars or avatars and other objects in the game. A player may also be enabled to control other aspects of a game.
One effect that plays a crucial role in the sense of reality in video games and other applications of virtual worlds is the effect of lighting. In the real world, as observed through a person's visual sense, lighting effects are crucial to understanding events, progression of events, and an ability to understand and make decisions about the surroundings. The same is true for a user observing the scenes and developing action in a video game or other representation of virtual reality. It is highly desirable in the art that lighting effects be as real as possible.
In a virtual reality video presentation at the time of filing the present patent application there may be one or more avatars, a relatively large number of stationary objects, such as landscape elements, a relatively large number of moving or moveable objects, such as vehicles, weapons, and the like, and one or more light sources to be considered in an ongoing video display. And the light sources may be of differing types and strengths, and may be applied in different directions. A virtual reality game video differs markedly from a pre-recorded video in that there is player interaction in the game video that determines where and how objects and avatars will be presented in succeeding frames of the video. The video is dynamic. So avatars will move, objects may move, and light sources may move, change, or be switched on and off, or may be altered in direction, intensity and/or color.
In current art calculating lighting effects for objects in a video game with a number of objects and a number of different light sources of perhaps different types, such as point source, parallel or cone effect, and with different directions is a considerable challenge. Generally in current art the cost (magnitude of computation) is proportional to the number of lights per object, so overall cost in a general way may be considered as proportional to the number of lights multiplied by the number of objects to render according to the light intensity and direction.
Methods have been developed to separate objects and light sources in a manner that the objects may be rendered and the lighting calculated for each as proportional to the number and intensity of the sources, but still in conventional art every frame, typically to be rendered thirty times per second, must be calculated from scratch for the lighting effects on every object.
The computing load for very busy videos, to keep them looking real, is a severe limitation to the number of objects and lighting variety that may be incorporated. What is clearly needed in the art is a new way to render lighting effects on objects in a dynamic video that has far less demand for computing power, but still renders very real effects.